1. Technical Field
The present invention generally relates to microfluidic systems, and, more particularly, to controlling chemical reactions in digital microfluidic systems.
2. Background Information
The creation of miniature biochemical analysis systems using microfabrication technology is a recent significant development in the field of microfluidics. These systems are often called micro total analysis systems or “lab on a chip” systems. These systems offer a number of advantages, including size reduction, power reduction, and increased reliability. However, current “lab on a chip” systems are typically tailored to a specific task. Therefore, it would be desirable to create reconfigurable and reprogrammable microfluidics systems capable of handling a variety of analysis tasks.
Digital microfluidic systems (DMFS) that use techniques such as electrowetting and dielectrophoresis are promising candidates for reconfigurable systems. One type of microfluidic system manipulates discrete droplets by electrowetting, where the interfacial tension of the droplets is modulated with a voltage. Droplets that are microliters in volume have been moved at 12-25 cm/sec on planar arrays of 0.15 cm wide electrodes. The ability to control individual droplets on a planar array, for example, enables complex chemical analysis operations to be performed in chemical “lab-on-a-chip” systems. For example, they can be used to perform DNA polymerase chain reactions for DNA sequence analysis and glucose assays. For many chemical analysis operations, no special purpose devices are required aside from the array itself. Systems utilizing such arrays have the potential to process hundreds of samples quickly. Thus, there is also a need for a method of concurrently coordinating the movements of a large number of droplets in a droplet-based system.